Re: libobjc2 2.2.1 segfaulting on aarch64 on Debian 13

to answer my own point. The issue was caused by a older runtime build of 
gnustep-base which was still lingering around.

When linking with -lgnustep-base the problem occured. Without 
-lgnustep-base,it didnt.

Maybe it would be smart to ignore the library or put up a more 
descriptive error than just segfaulting.


On 25.11.2025 04:53, Andreas Fink via Discussion list for the GNUstep 
programming environment wrote:
>
> Hello
>
> I am porting my code to Debian13 after running sucessfully running for 
> years under Debian 11 and 12.
>
> So I compiled the whole gnustep stack with not much hassle. When I try 
> to compile my own code however, it fails already at ./configure
>
> And it seems to be that ./configure runs a simple test to see if its 
> cross compiling or not where it fails.
>
> It boils down to this command line
>
> clang -o conftest  -fPIC -DLINUX -D_XOPEN_SOURCE=700 -D_POSIX_SOURCE 
> -D_DEFAULT_SOURCE -fobjc-arc -MMD -MP -DGNUSTEP 
> -DGNUSTEP_BASE_LIBRARY=1 -DGNU_GUI_LIBRARY=1 -DGNUSTEP_RUNTIME=1 
> -D_NONFRAGILE_ABI=1 -DGNUSTEP_BASE_LIBRARY=1 -fno-strict-aliasing 
> -fexceptions -fobjc-exceptions -D_NATIVE_OBJC_EXCEPTIONS -pthread 
> -fPIC -Wall -DGSWARN -DGSDIAGNOSE -Wno-import -I //include -fblocks 
> -fobjc-runtime=gnustep-2.2 -fblocks 
> -fconstant-string-class=NSConstantString -I. 
> -I/Users/afink/GNUstep/Library/Headers -I/usr/local/include 
> -I/usr/include  -DHAVE_OPENSSL=1   -pthread -fexceptions -rdynamic 
> -fobjc-runtime=gnustep-2.2 -fblocks 
> -L/Users/afink/GNUstep/Library/Libraries -L/usr/local/lib -L/usr/lib 
> -lgnustep-base -lpthread -l:libobjc.so.4.6 -lm -lssl -lcrypto  
> conftest.c -ldl -ldl
>
> a simple program in conftest.c:
>
> int main() { return 0; }
>
> compiling works but running produces a SIGSEGV.
>
> LLDB points to this line in the code
>
> (lldb) run
> Process 99524 launched: '/Users/afink/development/git/ulib/conftest' 
> (aarch64)
> Process 99524 stopped
> * thread #1, name = 'conftest', stop reason = signal SIGSEGV: address 
> not mapped to object (fault address: 0x0)
>     frame #0: 0x0000fffff7859088 
> libobjc.so.4.6`upgradePropertyList(l=0x0000fffff6e80402) at 
> legacy.c:328:11
>    325         }
>    326         size_t data_size = l->count * sizeof(struct objc_property);
>    327         struct objc_property_list *n = calloc(1, sizeof(struct 
> objc_property_list) + data_size);
> -> 328         n->count = l->count;
>    329         n->size = sizeof(struct objc_property);
>    330         for (int i=0 ; i<l->count ; i++)
>    331         {
>
>
> sizeof(struct objc_property_list) = 16
>
> sizeof(struct objc_property) = 40;
>
> (lldb) print *l
> (objc_property_list_gsv1) {
>   count = 712114218
>   next = 0x304036314900383a
>   properties = {}
> }
>
> so calloc fails with 712114218 * 40 * 16 bytes = 455GB...
>
> something is clearly not initialized
>
> Backtrace is this:
>
>     frame #0: 0x0000fffff7859088 
> libobjc.so.4.6`upgradePropertyList(l=0x0000fffff6e80402) at 
> legacy.c:328:11
>     frame #1: 0x0000fffff7858ecc 
> libobjc.so.4.6`objc_upgrade_class(oldClass=<unavailable>) at 
> legacy.c:357:20
>   * frame #2: 0x0000fffff78528cc 
> libobjc.so.4.6`__objc_exec_class(module=<unavailable>) at loader.c:352:19
>     frame #3: 0x0000fffff7fc1b4c 
> ld-linux-aarch64.so.1`___lldb_unnamed_symbol61 + 236
>     frame #4: 0x0000fffff7fc1c60 
> ld-linux-aarch64.so.1`___lldb_unnamed_symbol62 + 120
>     frame #5: 0x0000fffff7fd8360 
> ld-linux-aarch64.so.1`___lldb_unnamed_symbol236 + 96
>
>    349         // Load the classes from this module
>    350         for (unsigned short i=0 ; i<symbols->class_count ; i++)
>    351         {
> -> 352  objc_load_class(objc_upgrade_class(symbols->definitions[defs++]));
>    353         }
>
>
> These is what ccmake reports
>
>  BUILD_STATIC_LIBOBJC             ON
>  CMAKE_BUILD_TYPE                 RelWithDebInfo
>  CMAKE_INSTALL_PREFIX             /usr
>  CPACK_GENERATOR                  TGZ
>  CPACK_STRIP_FILES                ON
>  DEBUG_ARC_COMPAT                 OFF
>  EMBEDDED_BLOCKS_RUNTIME          ON
>  ENABLE_OBJCXX                    ON
>  ENABLE_TRACING                   OFF
>  FETCHCONTENT_BASE_DIR 
> /Users/afink/development/gnustep_build/libobjc2/build/_deps
>  FETCHCONTENT_FULLY_DISCONNECTE   OFF
>  FETCHCONTENT_QUIET               ON
>  FETCHCONTENT_UPDATES_DISCONNEC   OFF
>  GNUSTEP_CONFIG                   /usr/bin/gnustep-config
>  GNUSTEP_INSTALL_TYPE             SYSTEM
>  INCLUDE_DIRECTORY                objc
>  LEGACY_COMPAT                    OFF
>  LIBOBJC_NAME                     objc
>  M_LIBRARY /usr/lib/aarch64-linux-gnu/libm.so
>  OLDABI_COMPAT                    ON
>  STRICT_APPLE_COMPATIBILITY       OFF
>  TESTS                            OFF
>  TYPE_DEPENDENT_DISPATCH          ON
>  tsl-robin-map_DIR                /usr/share/cmake/tsl-robin-map
>
> I tried with OLDABI_COMPAT OFF and then it breaks at
>
> * thread #1, name = 'conftest', stop reason = signal SIGSEGV: address 
> not mapped to object (fault address: 0x0)
>     frame #0: 0x0000fffff785e774 libobjc.so.4.6`selector_lookup(char 
> const*, char const*) [inlined] 
> tsl::rh::power_of_two_growth_policy<2ul>::bucket_for_hash(this=0x0000000000000000, 
> hash=18399730721004063734) const at robin_growth_policy.h:125:19
>    122        * If bucket_count() is 0, it must always return 0.
>    123        */
>    124       std::size_t bucket_for_hash(std::size_t hash) const 
> noexcept {
> -> 125         return hash & m_mask;
>    126       }
>    127
>    128       /**
>
>
> libobjc was built with the following command line
>
>         export CC="/usr/bin/clang"
>         export CXX="/usr/bin/clang++"
>         export PREFIX="/"
>         export 
> PATH="/usr/GNUstep/System/Tools:/sbin:/bin:/usr/sbin:/usr/bin:/usr/local/sbin:/usr/local/bin"
>         export 
> PKG_CONFIG_PATH="/usr/lib/pkgconfig/:/usr/local/lib/pkgconfig/"
>         export RUNTIME_VERSION="gnustep-2.0"
>         export OBJCFLAGS="-fblocks"
>         export CFLAGS="-I ${PREFIX}/include"
>         export GNUSTEP_INSTALLATION_DOMAIN="SYSTEM"
>
>     cmake  .. -DCMAKE_BUILD_TYPE=RelWithDebInfo 
> -DBUILD_STATIC_LIBOBJC=1  -DCMAKE_C_COMPILER=${CC} 
> -DCMAKE_CXX_COMPILER=${CXX} -DCMAKE_INSTALL_PREFIX=/usr
>
> I tried with clang17,18,19 with same results
>
> anyone have an idea whats going rouge here?
>
>
>